Leaving a legacy to remove lifetime emissions

People born in previous decades have much higher lifetime emissions than those born today.  They should be encouraged to redress this by financing carbon dioxide removals as part of their legacy.

Climate change is widely acknowledged to raise substantial intergenerational equity issues.  Those born in earlier decades have produced many of the emissions leading to climate change.  But those born today will experience much greater damage.   This is especially true in the UK, where reductions in per capita emissions mean that previous generations have been responsible for much greater emissions over their lifetimes than will those born in recent years. 

This can be seen by looking at emissions per capita from the UK over time. (Throughout this post I refer to territorial emissions rather than consumption based emissions, data for which would anyway unavailable – see here for more on the two approaches.)  Chart 1 shows per capita emissions over time starting in 1800, shortly after the start of the industrial revolution.  Per capita emissions rose strongly in the 19th century, surpassing current levels around 1860. They remained high through most of the 20th century, beginning to decline from around the 1980s, and continuing to decline sharply this century. 

Chart 1: Per capita CO2 emissions in the UK since 1800 (ten year average)

Source: World Bank[i]  

Notes:  Data is an average over the following decade, so the figure for 1800 is the average of emissions from 1800 to 1809. Data for 2010 is an average of 2010 to 2019. Data going back over 200 years is clearly subject to large uncertainty, but here we are concerned with the broad levels and trends.  

The implications of this for emissions by those alive today can be seen more clearly by focussing on the last 80 years or so.  For the first half of this period (1940-1980) CO2 emissions remained between about 10 and 12 tonnes per capita. But they have since declined, roughly halving by 2019 relative to the first half of the period.  The UK’s legally binding obligation to reach zero by 2050 means this trend is set to continue.

Chart 2: Per capita CO2 emissions in the UK 1940 to 2020

Notes: data is as above, but annual rather than moving averages.

This means that different generations are on average responsible for different levels of emissions over their lifetimes. Chart 3 shows total lifetime emissions for an individual by year of birth, assuming that their emissions are equal to the national average in any year.  Someone born in 1940 would have average lifetime emissions of around 900 tonnes. This falls steadily over time so that someone born in 1980 would have lifetime emissions of around 400 tonnes.  Someone born today would expect total lifetime emissions of less than 100 tonnes, a factor of nearly 10 times less than someone born 80 years earlier.  Older people have thus on average contributed more to climate change, yet it is the young, and those yet to be born, who will mainly suffer the effects of carbon emissions. (These are averages with important exceptions – for example someone born in recent decades who takes a lot of flights will have higher emissions than even someone quite wealthy in previous generations.)

Chart 3: Indicative average lifetime emissions by year of birth

Note: Emissions are assumed to fall to net zero by 2050 and remain at that level thereafter. I have not assumed net negative emissions after 2050.  I have assumed a constant 80 year life span, ignoring changes in life expectancy. Again I am concerned with broad trends here, and this simplification makes little difference to the pattern. For example, for those born today an extended life will not add to lifetime emissions and may even reduce them, because emissions are assumed to be zero in the additional years, and negative emissions may reduce them further. 

There are clearly some qualifications to the conclusions from this analysis.  First, many of the people in the older groups would have spent much of their lives unaware of the harm to the climate due to emissions from burning fossil fuels.  It is only in the last 40 or 50 years or so that the effects on the climate of manmade emissions has become well established and well known science. Second, they were in any case largely powerless to eliminate the emissions.  For example, most would have had no control of the electricity generation mix or the use of fuel in industry.  Third, many of those born earlier have been poorer for those born today over their lifetimes, though not in all cases and not necessarily the young of today compared with their parents[1].

Nevertheless, the analysis clearly raises questions of whether those whose lives have led to higher emissions should be encouraged to redress the damage, provided that they can afford to do so. Similarly, the rich will typically emit more than the poor, so the cases for redress is stronger.

In practice is likely best done by some sort of carbon dioxide removal.  This most likely to be in the form of land use, engineering approaches to direct air capture Direct Air Capture being prohibitively expensive in this context and not yet available at scale.  Reforestation and rewilding in the UK seems a natural place to start, providing that there are appropriate quality thresholds and safeguards, including around permanence.  (For transparency I should say that around 10-15 years ago I balanced my own estimated lifetime emissions by financing an equivalent amount reforestation and rewilding in Scotland, with some safety margin built in.)

Indeed several reputable organisations already enable people to pay for planting trees to absorb emissions[ii]. The link may be explicit or implied.  For example, one organisation explicitly offers the ability to offset lifetime emissions by planting a single giant sequoia, which is large enough to absorb one person’s lifetime CO2[iii], although, as they acknowledge, it takes around two and a half centuries to do this, so it does not balance the effects of emissions now.

However, it is likely to prove challenging to get most people to spend money on this.  Even many better off older people are worried about their finances, especially the costs of care in later life.  And the sums involved are potentially not trivial – perhaps £10,000 depending on the cost of a particular project – although much smaller than other costs people might have to bear.  However there are various mechanisms by which this could be made easier.

One possible mechanism is to make use of assets remaining at the end of life, including by enhanced incentives under inheritance tax.   Charitable donations can already qualify for exemptions from inheritance tax.  People could be further encouraged to fund high quality reforestation and rewilding projects by granting additional incentives under inheritance tax rules.  This seems both in the spirit of it leaving a legacy for the future, something many people already try to achieve with bequests, and consistent with government policy objectives. 

Older people have contributed to climate change, although often unwittingly and in ways largely outside their control.  Providing incentives to give some of any accumulated wealth to redress damage look to be a worthwhile goal for public policy, and appears likely to be something many older people concerned for their grandchildren’s future would welcome. 

Adam Whitmore – 15th December 2021

[1] This is especially true looking at wealth rather than income, where many older people have benefitted from rises in asset prices.

[i]See  https://ourworldindata.org/co2-emissions, https://www.macrotrends.net/countries/GBR/united-kingdom/carbon-co2-emissions

[ii] For example https://www.nationaltrust.org.uk  (£5/tree) and https://treesforlife.org.uk/ (£6/tree) There are many junk offsets arounds also, which would be excluded from the type of system I am suggesting here.

[iii] https://onelifeonetree.com/  They estimate 1400 tonnes has been absorbed by the General Sherman, the world’s largest tree, over its life. 

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